Size dependent biexciton binding energies in GaN quantum dots

Abstract

Single GaN/Al(Ga)N quantum dots (QDs) have been investigated by means of microphotoluminescence. Emission spectra related to excitons and biexcitons have been identified by excitation power dependence and polarization resolved spectroscopy. All investigated dots exhibit a strong degree of linear polarization (∼90%). The biexciton binding energy scales with the dot size. However, both positive and negative binding energies are found for the studied QDs. These results imply that careful size control of III-Nitride QDs would enable the emission of correlated photons with identical frequencies from the cascade recombination of the biexciton, with potential applications in the area of quantum information processing.

Dynamic control of the optical emission from GaN/InGaN nanowire quantum dots by surface acoustic waves

“…3(e)) are consistent with the effect of lateral size variation of the confinement potential on the biexciton binding energy, as reported for III-Nitride QDs. 27,34,35 The observed trend can thus be explained by the effect of the SAW strain field and some possible contribution of the SAW-induced electric field parallel to the c-axis on the QD confining potential, 30 affecting the Coulomb interactions within the four-particle biexciton complex. A similar difference in modulation amplitude has been observed (although not discussed) in neutral and charged excitons in AlGaAs-GaAs core-shell nanowires.…”

“…Compression (tension) along the QD polar axis would result in an increase (decrease) of the electron-hole attraction J eh thus increasing (decreasing) E b XX . 27,34,35 The opposite holds for strain perpendicular to the polar axis, which would mainly affect the repulsive electron-electron (J ee ) and hole-hole (J hh ) interactions. Consequently, changes in E b XX with increasing SAW intensity (Fig.…”

Impact of biexcitons on the relaxation mechanisms of polaritons in III-nitride based multiple quantum well microcavities

“…28,29 In systems of reduced dimensionality, the biexciton binding energy varies in a nontrivial way as it depends on the confinement, the disorder, and the amplitude of the quantum-confined Stark effect inherent to III-nitride based heterostructures grown along the polar c axis. 30 In any case, in high-quality nitride-based MQW MCs, where the biexciton binding energy exceeds the exciton inhomogeneous broadening, it should be possible to observe additional emission features linked to the existence of biexcitons. 20 Alternatively, the formation of biexcitons could also play a 245308-1 1098-0121/2012/85(24)/245308 (13) ©2012 American Physical Society major role on the polariton laser threshold, as the LPB may be directly fed by the radiative dissociation of biexcitons.…”

Dynamic characteristics of the exciton and the biexciton in a single InGaN quantum dot

“…The biexciton binding energy of GaN QDs was recently found to scale with the dot size 9 and to exhibit both positive and negative values. 10 This opens for the possibility to obtain zero biexciton binding energy and thereby generate quantum entangled photon pairs in a cascade recombination of the biexciton. 11 In addition, measurements have revealed a strong polarization anisotropy of the photons emitted in the radiative decay of the excitons and the biexcitons for nitride based QDs, [12][13][14] which is attributed to the asymmetry of the confinement potential.…”